Method of producing metal in elongate form and semielliptical cross section



Sept. 26, 1967 J. P. LAGERMASINI ETAL 3,343,395

METHOD OF PRODUCING METAL IN ELONGATE FORM AND SEMIELLIPTICAL CROSS SECTION Filed June 16, 1965 [FIGS [F106 INVENTORS.

JOSEPH P. LAGERMASINI, KENNETH S. ROBERTS and JOSEPH E. SMITH ATTORNE Y.

United States Patent Ofifice ware Filed June 16, 1965, Ser. No. 464,318 5 Claims. (Cl. 72-206) This invention is directed to a process for producing metal in elongate form and of semielliptical cross section, and more particularly to such a process in which the desired cross sectional shape is obtained by drawing the metal through a die.

An important use of the present invention is in the manufacture of half round wire in which the cross section of the wire is substantially semicircular, and for purposes of simplifying an understanding of the invention it will be described hereinafter with reference to the production of half round wire. It will, of course be obvious from the following description that the process is equally applicable to the production of elongated metal shapes having cross sections falling into the more general de scription of semielliptical or which also are relatively large in cross sectional area, so as to be properly described as rod rather than wire. As used herein, the term semicircular is considered as a special case of the term semielliptical.

Half round wire may be made by means of a rolling operation or by drawing the metal through a die having a semicircular opening. However, there are certain objections to either method. The cost of appropriately machined rolls and the associated rolling apparatus tends to be appreciably higher than the cost of die drawing equipment of similar capacity. Furthermore, the wire produced by means of rolls may lack the desirable physical qualities of drawn wire. Although the alternative procedure of drawing through dies having semicircular openings may offer advantages insofar as equipment cost is concerned, the drawing process is complicated by the unsymmetrical shapes herein contemplated, there being a tendency toward non-uniformity in the extent of mechanical working and the resulting physical properties through the cross section of the wire.

It is, therefore, an object of the invention to provide a process for producing elongated metal shapes of semielliptical cross section which requires relatively simple and low cost equipment and which affords a final product of desirable physical properties.

A further object of the invention is to provide a process for producing half round wire in which the starting material may be selected from readily available stocks of standard circular cross section wires, and standard size circular dies may be used for drawing the wire to the desired half round shape.

Briefly, the method of the present invention is carried out by simultaneously drawing a pair of lengths of metal of generally rectangular cross section through a die having an elliptical opening. As the lengths of rectangular section enter the die, they are maintained in such position that a flat surface of one is against a flat surface of the other. These flat surfaces remain together in mutually supporting fashion as the lengths of metal are drawn through the die, and are thus preserved as the flat sides of the final desired lengths of semielliptical section. The drawn lengths are then separated and rolled onto spools or packaged or stored in lengths, depending on the physical characteristics and cross-sectional dimensions of the material. The simultaneous drawing of the two lengths makes possible the use of a drawing die having a full Patented Sept. 26, 1967 elliptical opening rather than a semielliptical die in which the sharp change in contour at the junctions of the straight edge of the die and the curved edge inherently introduces difliculties in the drawing operation and exaggerated variations in the physical properties of the metal across the cross section of the material produced.

Additional objects, features and advantages of the invention will be apparent from the following detailed explanation and the accompanying drawings in which:

FIG. 1 illustrates in schematic form apparatus which may be employed for producing half round wire in accordance with the method of the invention;

FIG. 2 is an enlarged cross section of the die 10 shown in FIG. 1, with two lengths of flattened wire entering the die opening from the left and being drawn into half round wire shown leaving the die opening at the right.

FIGS. 3, 4, 5, 6 and 7 show cross sections of the wire as it is formed by the apparatus of FIG. 1 at the positions A, B, C, D and B, respectively, FIG. 3 illustrating the cross section of the round wire used as a starting material in the process, and FIG. 7 illustrating the cross section of the final half round wire.

The apparatus shown in FIG. 1 actually comprises two identical sets of equipment operating in parallel for continuously forming two wires at the same rate of travel for each wire. Each equipment set includes a supply reel 1, a capstan 2 for pulling the wire through the drawing die of the equipment and a storage or take-up spool 3 on which the finally formed wire is reeled at the rate it is pulled through the apparatus by the capstan.

In the path of movement of the wire between the supply reel and the capstan are arranged a pair of driven flattening rolls 4, 5, idler rolls 6, 7, and 8 for guiding and orienting the wire prior to its entrance into the die 10, which is common to both sets of equipment, and idler roll 9 for guiding the drawn Wire between the die and the capstan.

In the operation of the apparatus, wire which may be of a circular cross section and of a standard stock size, as shown in FIG. 3, is rolled through the pair of driven flattening rolls 4, 5. The size of wire selected as a raw material for the method is dependent on the cross-sectional area of the half round wire to be produced. The crosssectional area of the wire supplied from the reel 1 should, of course be greater than the cross-sectional area of the desired half round wire to insure full contact of the surface of the wire with the die opening. However, the selection of the precise size of the starting wire selected for any particular operation depends on the physical properties of the metal of the wire and the temperature at which the drawing operation is accomplished. The criteria for this selection are substantially the same as those familiar to those skilled in the well known practice of drawing ordinary round wire.

In passing between the flattening rolls 4, 5, the crosssectional shape of the wire is changed from circular to generally rectangular as shown in FIG. 4. As the wire leaves these rolls, the wire has two opposed major flat surfaces produced by the contact with the roll surfaces. The two minor surfaces are unsupported during passage between the rolls and therefore are outwardly curved as shown in FIG. 4. The extent of flattening of the Wire is not extremely critical. However, Where the final wire is to be half round, i.e., of semicircular cross section, it is preferred to maintain the flattening rolls at a spacing such that the major transverse dimension of the flattened Wire is approximately twice the minor dimension.

After the two wires have been flattened as described above they are guided by means of idler rollers 6, 7 and 8 into position adjacent each other with a major flat face of each wire in contact with a major flat face of the other wire, the cross sections of the wire thus appearing as shown in FIG. 5. In this relative position the wires are drawn together and at the same rate through the circular die 10 as shown in FIG. 2. In passing through the die the cross section of the two wires is changed to the circular configuration illustrated by the cross-sectional view of FIG. 6. The change in shape is necessarily accompanied by at least a small amount of reduction in cross-sectional area to insure conformance of the transverse shape of the wire ot the shape of the opening in the die 10.

To insure that the two wires maintain their position adjacent each other until they have compleed their passage through the drawing die, cooperating idler rollers 9 are provided at the exit of the die. After the wires have passed between the rollers 9 they are separated as shown in FIG. 1 and after passing around the pulling capstans 2, are wound separately on the two storage reels 3.

It will be readily appreciated from the foregoing description of the present invention that half round wire of various sizes in which the dimension across the flat surface of the wire corresponds to standard stock circular wire diameters can be produced without the need for maintaining a second set of dies having semicircular openings. In addtion to this ecoomy of operating inherent in the method of the invention, the resulting half round wire normally possesses improved physical properties and surface appearance for the reason that the die opening presents no sharp'contours to the metal moving through it.

As a specifiic example of the use of the method herein described, and employing apparatus as shown in FIG. 1, a modybdenum half round wire was formed in the following manner. Molybdenum wires of 0.050 inch diameter circular cross section were drawn by capstans 2 from supply reels 1, heated by means of gas burners (not shown) to about 800-1000" C. and then passed through the two pairs of driven flattening rolls 4, 5. The wire leaving the flattening rolls was about 0.034 inch thick, and the maximum width of each wire was about 0.064 inch. The two wires were then guided into parallel abutting position as shown in FIG. 5 by means of idler rollers 6, 7 and 8. Just prior to the entrance of the pair of wires into the die 10 they were again heated by means of gas burners (not shown) to about 800-1000 C. The die opening was circular with a diameter of 0.062 inch. After the wires had been drawn through the die and between the idler rollers 9 they were separated and wound separately on storage reels 3. The resulting half round wire was 0.062 inch across the flat surface and was about 0.031 inch in thickness. It showed good surface and displayed physical properties substantially the same as those characteristic of circular wire drawn under the same conditions.

What is claimed is:

1. The process of producing metal in elongate form and of semielliptical cross section which comprises feeding to an elliptical drawing die a pair of lengths of metal of gener-ally rectangular cross section while maintaining the two lengths with a flat surface of each length in contact with a flat surface of the other length of said pair, drawing the lengths simultaneously and at the same rate through the die to reduce the cross section of each length from generally rectangular to semielliptical shape and separating the lengths after each portion thereof leaves the die.

2. The process of producing metal in elongate form and of semielliptical cross section which comprises flattening lengths of metal of circular cross section, feeding a pair of the resulting flattened lengths into an elliptical drawing die while maintaining a flat surface of one length of the pair against a flat surface of the other length, drawing the lengths together through the die to work the cross section of each length from substantially rectangular to semielliptical shape and thereafter separating the two lengths of metal from each other.

3. The process of producing metal in elongate form and of semilliptical cross section which comprises continuously feeding to an ellptical drawing die a pair of lengths of metal each having a flat surface of width less than a diameter of said die, arranging said lengths in parallel position with the flat surface of one length against the flat surface of the other length, drawing said lengths in the aforesaid position through the die and thereafter separating the lengths from each other.

4. The process of producing half round wire which comprises passing wire of circular cross section between a pair of spaced apart rolls, thereby flattening said wire, continuously orienting a length of the flattened wire parallel to a similarly flattened wire, with a flat surface of each length of wire against a flat surface of the other length of wire, continuously drawing the pair of lengths of wire together through a drawing die having a circular opening to form the two lengths of flattened wire into lengths of half round wire and thereafter separating said lengths of half round wire.

5. The process of producing half round wire which comprises simultaneously rolling two lengths of wire of circular cross section into lengths of flattened wire of generally rectangular cross section having a pair of opposed flat surfaces of width approximately double the thickness of the flattened wire, continuously orienting the two lengths in parallel arrangement with a flat surface of one length against a flat surface of the other length, drawing the two lengths simultaneously and at the same rate through a circular die having an opening of cross-sectional area less than the total cross-sectional area of the two flattened lengths to form each of the lengths into a length of wire of semicircular cross section and thereafter separating and separately reeling the lengths of semicircular cross section.

References Cited UNITED STATES PATENTS 1,384,448 7/1921 Gilbert et al. 72-278 CHARLES W. LANHAM, Primary Examiner.

H. D. HOINKES, Assistant Examiner. 

5. THE PROCESS OF PRODUCING HALF ROUND WIRE WHICH COMPRISES SIMULTANEOUSLY ROLLING TWO LENGTHS OF WIRE OF CIRCULAR CROSS SECTION INTO LENGTHS OF FLATTENED WIRE OF GENERALLY RECTANGULAR CROSS SECTION HAVING A PAIR OF OPPOSED FLAT SURFACES OF WIDTH APPROXIMATELY DOUBLE THE THICKNESS OF THE FLATTENED WIRE, CONTINUOUSLY ORIENTING THE TWO LENGTHS IN PARALLEL ARRANGEMENT WITH A FLAT SURFACE OF ONE LENGTH AGAINST A FLAT SURFACE OF THE OTHER LENGTH, DRAWING THE TWO LENGTHS SIMULTANEOUSLY AND AT THE SAME RATE THROUGH A CIRCULAR DIE HAVING AN OPENING OF CROSS-SECTIONAL AREA LESS THAN THE TOTAL CROSS-SECTIONAL AREA OF THE TWO FLATTENED LENGTHS TO FORM EACH OF THE LENGTHS INTO A LENGTH OF WIRE OF SEMICIRCULAR CROSS-SECTION AND THEREAFTER SEPARATING AND SEPARATELY REELING THE LENGTHS OF SEMICIRCULAR CROSS SECTION. 